1. Field of the Invention
The present invention relates to a method of manufacturing a toner, the toner, a developer, a developing device, and an image forming apparatus.
2. Description of the Related Art
Conventionally, a surface modification treatment for coating the surface of powder particles with a coating material has been performed in order to improve characteristics of the powder particles such as toner particles.
As a method for the surface modification treatment of the powder particles such as toner particles, a method is known that a mechanical stirring force is applied to the powder particles by a rotary stirring section such as a screw, a blade, or a rotor to fluidize the powder particles in a powder flowing passage and a coating material is ejected from a spray nozzle to the powder particles in a fluidized state. For example, Japanese Examined Patent Publication JP-B2 5-10971 (1993) discloses a surface modification method of solid particles in which a rotary stirring section is rotated at peripheral speed of 5 to 160 m/sec to fluidize powder particles and a liquid is sprayed from a spray nozzle to the powder particles in a fluidized state to adhere fine solid particles contained in the liquid to surface of the powder particles or to form a film of a coating material contained in the liquid on the surface of the power particles. According to the surface modification method disclosed in JP-B2 5-10971, adhesiveness between the coating material and the powder particles is able to be improved and time required for the surface modification treatment is able to be shortened.
Further, Japanese Unexamined Patent Publication JP-A 4-211269 (1992) discloses a method for manufacturing a microcapsule in which resin particles are adhered to the surface of inner core particles and are treated with a solvent that dissolves the resin particles to form a coating layer on the surface of the inner core particles. The method for manufacturing a microcapsule disclosed in JP-A 4-211269 comprises at least a step of adhering the resin particles to the surface of the inner core particles, a step of treating resin particles with a solvent that dissolves the resin particles, and a step of drying and collecting the treated particles.
However, in the production method disclosed in JP-B2 5-10971, aggregation of powder particles and coating material is caused depending on the structure of spray nozzle. In the case of using a spray nozzle having a structure such that the spray nozzle comprises a liquid pipe and an air pipe, the liquid pipe is inserted in the air pipe such that an axis of the liquid pipe coincides with an axis of the air pipe, and liquid is blown about by pressure of air at the tip of the spray nozzle to atomize the liquid, when circulation wind, powder particles, coating material and the like collide with the spray nozzle, deviation occurs in central axes of the liquid pipe and the air pipe, and bias is generated in air flow per unit area in the cross-section of an ejection port of the air pipe. Then a spraying direction of liquid is greatly changed, and the liquid is difficult to be gasified. As a result, liquid concentration in a powder passage is greatly changed, and dew condensation due to rapid increase in liquid concentration, aggregation of toner base particles with each other, and adhesion of the particles to a powder passage may occur.
Since the treatment is performed by using the solvent that dissolves a resin of the resin particles in the method disclosed in the JP-A 4-211269, the solvent taken in the resin of the resin particles hardly vaporizes and a large amount of the aggregates are generated even when the inner core particles and the resin particles are fluidized at high speed. Further, large amounts are adhered to the inner wall of the apparatus, which are difficult to be collected in a state of primary particles, and the method does not provide excellent productivity. There is a possibility that some kinds of solvents dissolve even the inner core particles so that waxes contained in the inner core particles and the like are adhered and exposed to the surface of the inner core particles as particles, and when using the obtained microcapsule particles as a toner, toner performance including storing performance and fixing performance of the toner is deteriorated.